The present disclosure is directed to a control system for operating a processing line with a sheet metal descaler. The descaling of the sheet metal may be accomplished via a slurry or a dry abrasive shot blast method. The descaling medium may be propelled against the sheet metal via rotary wheels or impellers. A control with sensors may be used to automatically adjust the spray blast pattern produced by impeller wheels and/or the sheet metal advance rate during descaling of the sheet metal.